Defence and safety
Modern bridges today currently have a design life requirement of around 120 years, with that said, the performance of the protective system is thus a highly important factor. One of the biggest culprits responsible for bridge failure is corrosion. For example, the Genoa Bridge which collapsed in 2018 due to harsh weather conditions, killing 43 and leaving 600 people homeless. Bridge maintenance is an area where changes and protection can provide profound savings if institutional inertia can be overcome.
How can Corrosion weaken bridges?
- Reduces the strength of structural elements, causing unexpected and unintended bridge performance. It lowers the axial and flexural strength, leading to complete or partial failure or the bridge.
- Lowered shear capacity, reducing the effectiveness of cross sectional areas of major bridge components. This leads to friction, vibration and concussive action that the overall structure may not be able to sustain in the long term.
- Increased fatigue which also impacts the strength of steel components and connections, accelerating the cracking and pitting of corrosion. Corrosive damage such as the above, is usually likely to be invisible, occurring in hidden and hard to reach places, thus increasing likelihood of catastrophic unforeseen failures.
- Decreases the bond strength due to steel expanding when it corrodes. This weakens structural components, contributing to failure.
- Diminished ductility, due to corrosion lowering the ability of metal bridge sections to bend and twist. The inability of metal parts to flex when exposed to harsh conditions and heavy traffic loads is responsible for some of history’s greatest bridge failures.
From the continued development of coating technology at Sherardize UK we are able to provide bridges with an extended and reliable life cycle, with very low maintenance needs. Sherardizing is important to ensure that the protective coating can be applied to all internal and external surfaces, to avoid creation of water and dirty traps that would encourage corrosion, ensuring future inspections and maintenance can be carried out effectively. To provide further protection, a duplex coating can be applied to ensure good adhesion and prolonged protection.
Applications:
- Rollers
- Safety Anchor Bolts
- Base Plates
- Bracing Plates
- Panel Pins